The present invention relates to an igniter assembly for controlling the current supply to a primary winding of an ignition coil of an internal combustion engine.
An example of a known igniter assembly is illustrated in FIGS. 4 and 5. The illustrated assembly includes a casing 1, an electronic circuit unit 2 in the form of a power transistor housed in the casing 1, a connector 3 attached to the casing 1, a plurality of connector terminals 4, a plurality of connecting leads 5 having opposite ends which are soldered 6 to the connector terminal 4 and the power transistor unit 2 respectively, for providing electrical connection therebetween, and a cover 7 for covering an opening formed in the casing 1. The connector 3 is adapted to be connected to an ignition coil for providing electrical connection between an unillustrated ignition coil and the electronic circuit unit 2 through the connector terminals 4, so that the electronic circuit unit 2 controls the current supply to a primary winding of the ignition coil which has a secondary winding connected through a distributor to unillustrated ignition plugs for cylinders of an engine.
The conventional assembly is constructed as follows. First, the power transistor unit 2 is inserted in the casing 1 to which the connector 3 is then attached. In this connection, the connector 3 may be attached to the casing 1 in advance before the power transistor unit 2 is placed in the casing 1. Thereafter, one end of each connecting lead 5 is soldered to the connector terminal 4, and the other end thereof to the power transistor unit 2. After the soldering of the connecting leads 5, the cover 7 is secured to the casing 1 for covering the opening therein.
In operation, when a control signal is supplied to the power transistor unit 2, the unit 2 controls, based on the control signal, the current supply to a primary winding of an unillustrated ignition coil, which is adapted to be connected to the connector 3, so that a high voltage will be developed across a secondary winding thereof based on the current supplied to the primary winding. The high voltage thus developed is then fed through an unillustrated distributor to spark plugs (not shown) for firing the cylinders of an engine.
With the conventional igniter assembly as constructed above, connecting leads 5 are required for providing connection between the connector terminals 4 and the power transistor unit 2 and, furthermore, the leads must be connected at opposite ends thereof to the terminals 4 and transistor 2, respectively, by a solder 6, resulting in an increase in assembly steps and adding to the cost of manufacture.